st: Error "too many options" in twoway graph

Hello list,
I'm using the following code to generate a series of graphs:
levels table , local(mtable)
foreach mt in `mtable' {
preserve
keep if table == `mt'
local t1 = serie + ". " + titre1
local t2 = titre2
local t3 = titre3
local t4 = titre4
local t5 = titre5
twoway (scatter y year , title(,justification(left) size(tiny) ) )
|| lfit y year , ///
by(affect1a, subtitle("`t1'" "`t2'" "`t3'" "`t4'" "`t5'"
,justification(left) ) caption("`note'`mt'" , size(tiny))) ///
ylabel(, angle(horizontal))
restore
}
This works fine for most of the values of mt, but for two values I get a
"too many options" error message. These two values would generate only two
graphs on each page (according to affect1a), i.e. fewer than most of the
other pages which are generated without problem. The data used for the
graphs are fine, no missing values, right type, etc.
Thanks for any help.
Andre
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